Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
  • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/02—Details
  • H01H33/59—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the ac cycle
  • H01H33/596—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the ac cycle for interrupting dc
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
  • H02H3/02—Details
  • H02H3/025—Disconnection after limiting, e.g. when limiting is not sufficient or for facilitating disconnection
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
  • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
  • H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
  • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
  • H02H7/28—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for meshed systems
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
  • H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
  • H02H9/023—Current limitation using superconducting elements
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N60/00—Superconducting devices
  • H10N60/30—Devices switchable between superconducting and normal states
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
  • Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

Definitions

• the invention relates to high voltage direct current transmission and / or distribution networks, generally designated by the acronym HVDC.
• HVDC high voltage direct current transmission and / or distribution networks
• the invention relates in particular to the selectivity and continuity of service of an HVDC network when a fault occurs.
• HVDC networks are particularly envisaged as a solution to the interconnection of disparate or non-synchronous electricity production sites, appearing with the development of renewable energies.
• HVDC networks are particularly envisioned for the transmission and distribution of energy produced by offshore wind farms rather than AC technologies, due to lower line losses and the lack of impact of network noise on long distances.
• Such networks typically have voltage levels of the order of 50 kV and higher.
• a sectioning can be carried out via a converter at the end of the line, provided with a circuit breaker on the AC side.
• the sectioning can no longer be performed by such a converter in multipoint or multino transmission.
• Disconnection of direct current in such networks is a crucial issue directly conditioning the feasibility and development of such networks. Indeed, the occurrence of a short circuit at a node propagates very quickly throughout the network. In the absence of a fairly fast cut at the node, the short-circuit current continues to grow and can reach several tens of kA in a few ms. The short-circuit current can then exceed the breaking capacity of the DC circuit breakers of the different nodes. The short-circuit current could also damage the power electronics used in the AC / DC converters at the nodes of the network.
• the invention aims to solve one or more of these disadvantages.
• the invention aims in particular to optimize the selectivity and continuity of service of the high voltage network in case of failure, and those with electrical equipment at a reasonable cost.
• the invention thus relates to a method for protecting a high-voltage direct current electrical network, as defined in appended claim 1.
• the following different features may also be combined with the features of the dependent claims, each of which features may be combined with the features of claim 1 without constituting an intermediate generalization.
• the invention also relates to a high-voltage direct current electrical network, as defined in the appended claims.
• FIG 1 is a simplified example of a high-voltage DC network for the implementation of the invention.
• FIG. 2 is a simulation diagram of currents flowing through different converters during a failure
• FIG. 3 is a diagram of simulation of the input voltages of different converters during a failure
• FIG. 4 is a diagram of simulation of the voltages on interconnection nodes during a failure
• FIG. 5 is a simulation diagram of currents flowing through switches at the ends of a short-circuit line.
• FIG. 1 is a simplified schematic representation of an example of a DC high voltage network 1 comprising interconnection nodes 10, 20 and 30.
• the simplified network 1 illustrated here comprises high voltage lines 120, 130 and 230.
• the network 1 is here illustrated in a simplified way in a unipolar configuration.
• the line 120 is intended to connect the interconnection nodes 10 and 20
• the line 130 is intended to connect the interconnection nodes 10 and 30,
• the line 230 is intended to connect the interconnection nodes 20 and 30.
• Each Interconnect node includes a connection interface to high voltage lines, and a connection interface to a local area network.
• Converters 16, 26 and 36 of the modular multi-level type or MMC for Modular Multi-Level Converter in English language) are connected to the respective local network connection interface of the interconnection nodes 10, 20 and 30.
• the converters 16, 26 and 36 are half-bridge type.
• the converters 16, 26 and 36 are associated with alternative local networks or equipment (for example electric generators such as wind turbine fields, tidal power plants, nuclear power plants, thermal power plants or photovoltaic generators, or networks transport or consumer premises).
• the converters 16,26 and 36 control, in a manner known per se, the power flow between their alternative interface and their continuous interface.
• the MMC converter 16 is connected to the local network interface of the interconnection node 10 via a protection circuit.
• This protection circuit comprises a switch 1 1, connected to the local network interface of the interconnection node 10.
• the protection circuit furthermore comprises a split circuit connected in series with the switch 1 1, between a continuous input of the converter 16 and the local network interface of the interconnection node 10.
• the split circuit comprises first and second branches connected in parallel.
• the first branch comprises a switch 12 connected in series with a current limiter 13.
• the second branch comprises a switch 14 connected in series with a current limiter 15.
• the switch 1 1 is here a mechanical type circuit breaker.
• the switch 1 1 is selected in particular to provide a breaking capacity between the interconnection node 10 and the converter 16.
• the current limiter 13 and the current limiter 15 are of the superconducting short-circuit current limiting type. or SCFCL.
• Switches 12 and 14 are here controlled switches with fast switching.
• the high voltage line 120 is connected to the interconnection node 10 via a switch 1 12.
• the switch 1 12 is here a mechanical type circuit breaker. Although not illustrated, a fast switching controlled disconnector can be connected in series with the switch 1 12 between the high voltage line 120 and the interconnection node 10.
• the high voltage line 130 is connected to the interconnection node 10 by via a switch 1 13.
• the switch 1 13 is here a mechanical type circuit breaker.
• a fast switching controlled disconnector can be connected in series with the switch 1 13 between the high voltage line 130 and the interconnection node 10.
• the MMC converter 26 is connected to the local network interface of the node interconnection 20 via a protection circuit.
• This protection circuit comprises a switch 21, connected to the local network interface of the interconnection node 20.
• the protection circuit furthermore comprises a split circuit connected in series with the switch 21, between a continuous input of the converter 26 and the local network interface of the interconnection node 20.
• the split circuit comprises first and second branches connected in parallel.
• the first branch comprises a switch 22 connected in series with a current limiter 23.
• the second branch comprises a switch 24 connected in series with a current limiter 25.
• the switch 21 is here a mechanical type circuit breaker.
• the switch 21 is in particular selected to provide a breaking capacity between the interconnection node 20 and the converter 26.
• the current limiter 23 and the current limiter 25 are here of the short-circuit current limiting type above. driver or SCFCL.
• the switches 22 and 24 are here controlled switches with fast switching.
• the high voltage line 120 is connected to the interconnection node 20 via a switch 212.
• the switch 212 is here a mechanical type circuit breaker.
• a fast switching controlled disconnect can be connected in series with the switch 212 between the high voltage line 120 and the interconnection node 20.
• the high voltage line 230 is connected to the interconnection node 20 by means of intermediate switch 223.
• the switch 223 is here a mechanical type circuit breaker.
• a fast switching controlled disconnector can be connected in series with the switch 223 between the high voltage line 230 and the interconnection node 20.
• the MMC converter 36 is connected to the local network interface of the interconnection node 30 via a protection circuit.
• This protection circuit comprises a switch 31, connected to the local network interface of the interconnection node 30.
• the protection circuit furthermore comprises a split circuit connected in series with the switch 31, between a continuous input of the converter 36 and the local network interface of the interconnection node 30.
• the split circuit comprises first and second branches connected in parallel.
• the first branch comprises a switch 32 connected in series with a current limiter 33.
• the second branch comprises a switch 34 connected in series with a current limiter 35.
• the switch 31 is here a mechanical type circuit breaker.
• the switch 31 is in particular selected to provide a breaking capacity between the interconnection node 30 and the converter 36.
• the current limiter 33 and the current limiter 35 are here of the short circuit current limiting type to superconductor or SCFCL.
• the switches 32 and 34 are here quick-switched controlled disconnectors.
• the high-voltage line 130 is connected to the interconnection node 30 via a switch 323.
• the switch 323 is here a mechanical type circuit breaker.
• a fast switching controlled disconnector can be connected in series with the switch 323 between the high voltage line 230 and the interconnection node 30.
• the high voltage line 130 is connected to the interconnection node 30 by the intermediate switch 313.
• the switch 313 is here a mechanical type circuit breaker.
• a disconnector The fast switching control unit can be connected in series with the switch 313 between the high voltage line 130 and the interconnection node 30.
• Controlled switches 1 1, 1 12, 1 13, 21, 212, 223, 31, 313 and 323 are advantageously mechanical circuit breakers, in particular because of the low losses in line that they are capable of generating.
• the current limiters 15, 25 and 35 are sized to maintain the short-circuit current passing through them at a level below the breaking capacity of the switches 12 and 13, 212 and 223, 313 and 323, respectively.
• the current limiters 15, 25 and 35 thus guarantee the effective opening of the switches 1 12 and 1 13, 212 and 223, 313 and 323 respectively, in the event of occurrence of a short-circuit.
• the current limiters 13, 23 and 33 are sized to maintain the current passing through it at a level below the breaking capacity of the switches 12 and 13, 212 and 223, 313 and 323 respectively.
• the current limiters 13, 23 and 33 thus guarantee the effective opening of the switches 1 12 and 1 13, 212 and 223, 313 and 323 respectively, in case of occurrence of a short-circuit.
• a communication network (shown in dash-dot) is created at the interconnection node 10 between the switches 1 1, 1 12 and 1 13.
• a communication network (shown in dash-dot) is created at the node interconnection 20 between the switches 21, 212 and 223.
• a communication network (shown in dash-dot) is created at an interconnection 30 between the switches 31, 313 and 323.
• a communication network (shown in broken lines) is created between the interconnection node 10, the switch 11, the switch 12, the switch 14, the limiters 13 and 15, and the converter 16.
• a network of communication (shown in dashed line) is created between the interconnection node 20, the switch 21, the switch 22, the switch 24, the limiters 23 and 25, and the converter 26.
• a communication network (illustrated in FIG. discontinuous line) is created between the interconnection node 30, the switch 31, the switch 32, the switch 34, the limiters 33 and 35, and the converter 36.
• a communication network is created between the switches 1 12 and 212.
• a communication network is created between the switches 223 and 323.
• a communication network is created between the switches 1 13 and 313.
• a local control circuit 19 keeps the switches 11, 14, 12 and 13 closed, and keeps the switch 12 open;
• a local control circuit 29 keeps the switches 21, 24, 212 and 223 closed, and keeps the switch 22 open;
• a local control circuit 39 holds the switches 31, 34, 313 and
• the operation of the protection of the network 1 will now be detailed in a case where a short-circuit to earth occurs on the line 230 (or a short circuit between core and cable screen for example), near the switch 323.
• the short-circuit current is propagated throughout the network.
• the protection will aim to implement the following steps:
• the identification of the faulty line can be carried out as follows:
• a fault is detected in a non-synchronized manner at each interconnection node 10, 20 and 30.
• the fault detection is performed in a manner known per se at each interconnection node by voltage and current measurements. local;
• each converter 16, 26, 36 activates its internal protection. Since an MMC converter is not designed to withstand high short-circuit currents (an MMC converter is generally sized for a maximum current of 4 kA), the internal protection of each MMC converter 16, 26 and
• Each MMC converter 16, 26 or 36 activated no longer ensures control in voltage and power;
• the respective current limiter 15, 25 or 35 is then traversed by a fault current. This current limiter is then activated.
• the respective current limiters 15, 25 and 35 will thus be activated in an unsynchronized manner, as can be seen in the diagram of FIG. 2.
• the short circuit current supplied by each MMC converter drops below 2 kA, once the corresponding current limiter is activated. Because of the current limitation, for each MMC converter 16, 26 or 36, there is a certain time in order to identify the faulty high-voltage line;
• FIG. 5 is a diagram of the currents through the switches 223 (in dotted lines) and 323 (in solid lines) at the occurrence of the short circuit.
• a control circuit of the node 30 receives the measurements coming from the switch 223 and the switch 323 (at least the direction of current flowing through these switches, advantageously the voltage and current measured at these switches), to deduce that the line 230 is faulty and this defect is close to the switch 323.
• an algorithm for local detection of a fault of the high-voltage line can be used, so that a node connected to this high-voltage line provides an opening command of the high-voltage line. controlled switch of the other node connected to this high-voltage line.
• a control circuit of the interconnection node 20 receives the measurements from the switch 223 and the switch 323, or the opening order of the switch 223, to deduce that the line 230 is in fault and that this fault is close to the switch 323;
• the fault isolation step can be performed as follows:
• the switches (or mechanical circuit breakers) 1 12, 1 13, 212, 223, 313 and 323 have a breaking capacity of 8 kA.
• the breaking capacity of the switches of the high voltage lines of the network 1 is dimensioned in a manner known per se as a function of the size of the network 1 and the number of stations connected to it.
• the current maximum fault Idm N * 2 * ln.
• the fault current is eliminated by controlling the opening of the switches 223 and 323.
• a delay of 17 ms is here observed.
• the voltage is raised on the network 1.
• the internal protection of the MMC 16, 26 and 36 converters is activated.
• these MMC converters can only resume their control in voltage and power if the voltage at their DC input exceeds about 0.7 times the rated voltage.
• the current through the current limiters 15, 25 and 35 gradually decrease.
• the respective voltages on the local network interfaces of the interconnection nodes 10, 20 and 30 reach 0.7 times the nominal voltage;
• the MMC converters 16, 26 and 36 are informed respectively by the interconnection nodes 10, 20 and 30 that the respective voltages on their local network interfaces reach 0.7 times the nominal voltage.
• the MMC converters 16, 26 and 36 then resume their voltage control, so as to raise the voltage on the high voltage lines 120 and 130 to the nominal value.
• the output voltage of the MMC converters 16, 26 and 36 also progressively rises to the nominal level.
• the current limiters 15, 25 and 35 are then still activated in the resistive state and traversed by nominal currents. These current limiters 15, 25 and 35 can not return to the superconducting state without interrupting their conduction.
• the currents of the MMC converters 1 6, 26 and 36 then cross respectively the current limiters 13, 23 and 33 which are in the superconducting state.
• the currents of the MMC converters 16, 26 and 36 then no longer cross the current limiters 15, 25 and 35.
• the output voltage of the MMC converters 16, 26 and 36 is equal to the voltage at the respective local area network interface of the interconnection nodes 10, 20 and 30.
• the control The power of the MMC converters 16, 26 and 36 can then be resumed.
• the power flow through the high voltage lines 120 and 130 can then also be resumed.
• the switches 14, 24 and 34 can be opened, so that the current limiters 15, 25 and 35 can gradually return to their superconducting state, for later use.
• each of the current limiters makes it possible in particular to restore a nominal current for the MMC converters 16, 26 and 36 in a reduced time.
• the current limiters 13 and 15, 23 and 25, or 33 and 35 can use the same cooling tank, to limit their cost.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Emergency Protection Circuit Devices (AREA)
• Supply And Distribution Of Alternating Current (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (5)

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• 2016
  • 2016-09-14 FR FR1658595A patent/FR3056033B1/fr not_active Expired - Fee Related
• 2017
  • 2017-09-11 CN CN201780056012.8A patent/CN109964382A/zh active Pending
  • 2017-09-11 EP EP17780469.7A patent/EP3513478A1/de not_active Withdrawn
  • 2017-09-11 US US16/332,599 patent/US10951034B2/en active Active
  • 2017-09-11 WO PCT/FR2017/052407 patent/WO2018050997A1/fr unknown

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